Gastrointestinal Amyloidosis: A Rare Cause of Chronic Diarrhea

Abstract

Introduction: GI manifestations of amyloidosis include GI bleeding, malabsorption, protein losing enteropathy and rarely chronic gastrointestinal dysmotility. We present a case of amyloidosis-related chronic gastrointestinal dysmotility that presented as chronic diarrhea. Case: A 65 year old male was transferred from an outside hospital for a 6 month history of diarrhea and orthostatic hypotension. He had a history of diabetes and hypertension and had been hospitalized for a month prior to transfer. Orthostasis workup included CT head, carotid US, random cortisol and cosyntropin stimulation test which were all normal. Echocardiogram was done to rule out cardiac causes of orthostasis and showed an EF of 55%, mild LV hypertrophy and diastolic dysfunction. Chronic diarrhea workup included fecal leukocytes, Giardia stool antigen, C. difficile toxin PCR, stool microscopy and culture, US abdomen, CT abdomen, EGD, colonoscopy and celiac panel which were all normal. Orthostasis was felt to be due to volume depletion from diarrhea and autonomic dysfunction.On arrival he was notably orthostatic with BP dropping from 156/90mmHg to 74/44mmHg and was treated aggressively with IV fluids, increasing doses of fludrocortisone and midodrine. He continued to have 5-6 loose bowel movements daily despite loperamide. EMG showed advanced sensory and motor polyneuropathy thought to be due to DM. A repeat echo showed an EF of 60% and severe concentric LV hypertrophy with increased echogenicity. Cardiac MRI showed severe left ventricular hypertrophy with evidence of delayed hyper enhancement in the mesocardial anterior septum and anterolateral walls on delayed images consistent with cardiac amyloidosis. A fat pad biopsy followed by a repeat EGD and colonoscopy with duodenal and colonic biopsies were all positive for AL amyloid. Diarrhea improved with Lomotil and he was discharged with a follow up with Hematology. Discussion: Chronic diarrhea is a rare presentation of gastrointestinal amyloidosis. Only 3% of the cases of amyloidosis have biopsy proven amyloid involvement of the GI tract. Of these, approximately 80% have systemic amyloidosis at the time of diagnosis. Considering the non-specific appearance of GI amyloidosis on endoscopy/colonoscopy, the diagnosis requires a tissue biopsy with confirmatory staining or amyloid fibrils seen on electron microscopy. It is important to consider the diagnosis of amyloidosis while evaluating chronic diarrhea with other systemic manifestations.Figure 1Figure 2Figure 3